I just got hold of a Asus CUV4X-DLS dual socket 370 board, and am finding that, while it works fine with a single CPU, it won't boot with two installed:

- CPUs are PIII 1000/256/133 and work together in another dual board
- The system 'starts' (fans spin) but there's no video and no beeps - it just hangs
- The system boots fine with one CPU
- I can swap the CPUs round when booting with one CPU and it still works
- Resetting the CMOS doesn't change anything
- I have a POST card (https://www.amazon.com/dp/B008BZBKXC) which works fine in an ISA slot on another board, but doesn't show any POST codes (even when the single CPU config boots)
- The second CPU seems correctly seated
- 4x 256GB PC133 sticks are installed (which also work fine in a second board)
- The auto-config jumper is set (I guess I could try disabling this and manually clocking everything down)

Any suggestions? I have a multimeter and oscilloscope, and am comfortable with SMT soldering. My first instincts would be to inspect the board for damage and otherwise attempt to clean the CPU socket with isopropyl and inspect the caps before checking voltages (there appear to be two sets of regulators for each CPU, albeit I obviously lack a schematic). Thanks!